Activity 8 & 9 & 10 Flashcards

Flashcards for reviewing key concepts from Activities 8, 9, and 10, covering transcription, translation, the lac operon, Hardy-Weinberg principle, phylogenetic trees, and evolution terminology.

What are the two major steps involved in expressing genes as proteins?

Transcription (DNA to RNA) and translation (RNA to proteins).

What three components make up DNA?

Phosphate, deoxyribose sugar, and a nitrogenous base.

Name the two types of nitrogenous bases.

Purines and pyrimidines.

What is the shape of a DNA molecule?

Double helix.

What nitrogen base pairings are correct during transcription?

C & G and A & U.

How many nucleotides make up mRNA codons?

Three.

What direction are codons written in?

5' to 3'.

Why must codons be read by starting at the right place?

Because codons are commaless.

What codon tells the ribosome where to begin reading?

The start codon (methionine).

What are the three bases of the start codon?

AUG.

What do stop codons signal to the ribosome?

Where to stop reading.

What are the three stop codons?

UAA, UAG, and UGA.

What are the three stages of transcription?

Initiation, elongation, and termination.

What directs where transcription begins?

Promoter.

What is the part of the gene copied into RNA?

Transcription unit.

What is the effect of a nonsense mutation?

Codon changed to stop and premature termination of polypeptide.

What is the effect of a missense mutation?

Altered amino acid.

What is the effect of a silent mutation?

No change in amino acid.

What is the effect of a frameshift mutation?

Reading frame off by one and amino acids altered from point of mutation.

Why is a poly(A) tail added to the RNA molecule during pre-mRNA processing?

The addition of the poly(A) tail protects the RNA molecule from aggressive enzymes in the cytoplasm, allowing the RNA molecule to be exported into the cytoplasm for translation.

What is alternative splicing?

When one pre-mRNA molecule may be spliced in two or more different ways, depending on which exons are kept.

How does wobble pairing benefit protein synthesis?

The ability of the third codon to pair with greater flexibility reduces the number of tRNA required for protein synthesis, streamlining the translation process and making it more efficient.

What may a frameshift mutation involve?

The deletion or insertion of one, two, or four base pairs into the DNA sequence, causing the reading frame to be off by one base pair from the mutation onwards.

What is the lac operon required for?

The transport and metabolism of lactose.

When glucose is not available, what can the lac operon digest?

Lactose.

Which of the following statements regarding the lac operon is false?

Allolactose binds to the lac repressor when lactose levels are low.

Which of the following statements regarding the lac operon is true?

A promoter is the site where RNA polymerase binds to the lac operon.

Which sugar mediates the activity of the lac repressor?

Allolactose.

On which sugar does the CAP-cAMP complex depend?

Glucose.

According to the Hardy-Weinberg principle, what five conditions must be met to maintain equilibrium (i.e. no evolution)?

No mutations, no gene flow, random mating, large population size, and no selection.

What do the Hardy-Weinberg formulas allow scientists to look at?

Whether evolutionary forces are acting on a population by detecting changes in the gene frequencies of the population over time.

What is one of the Hardy-Weinberg formulas for genotypes?

p2 + 2pq + q2 = 1

What is one of the Hardy-Weinberg formulas for alleles?

p + q = 1

Which one of these scientists were pre-Darwin?

Jean-Baptiste de Lamarck

Who independently came up with the theory of evolution?

Alfred Wallace & Charles Darwin

Which one of the following is NOT a force of microevolution?

Artificial selection

These mutations are quickly eliminated from the population.

Lethal mutations

Random phenomenon that results in the loss of alleles and reduced genetic variability.

Genetic drift

Small populations are more sensitive to genetic drift than large populations.

True

Which species is the closest relative of domestic cats?

African wild cat

Which clade is the sister taxon to tigers?

Jaguar-Lion-Leopard clade

Choose the statement that is true in the phylogeny above.

Cats in box A evolved from a common, small bodied, cat-like ancestor

All cats shown evolved from a cat-like ancestor not alive today.

True

What is Change in frequency of a character due to the role of chance is termed?

Genetic drift

What is An organism or population that gives rise to two or more descendants/populations termed?

Common ancestor

What is the term when An organism intermediate in some characters between two other organisms termed?

Transitional form

What is the term when a Group of genetically similar interbreeding individuals is?

Population

What term is the Observable characteristics of organisms?.

Phenotype

What is the term Divergence in populations resulting in reproductive isolation?

Speciation

What is Heritable information encoded in DNA?

Genotype

What is the term Di erential survival of di erent phenotypes that cause a change in genotype frequencies?

Natural selection

What is the term Change in heritable characteristics of biological populations over time?

Evolution

What is the term An evolutionary tree, depicts a hypothesis about patterns of relationship among species?

Phylogeny

What is the term A change in genotype?

Mutation

What is the term Closely related species that have recently evolved from a common ancestor by adapting to di erent parts of the environment?

Adaptive radiation

What is A type of incompatibility that is found equally often in plants and animals and occurs when the ovule is fertilized but the zygote develops into an individual with reduced viability?

Post-zygotic isolation

What is Acquisition of the same biological trait in unrelated lineages (example: the wing)?

Convergent evolution

What is The process whereby one population speciates in response to and in concert with another, and is a consequence of the associate’s dependence on its host for its survival?

Co-speciation

What is The accumulation of di erences between groups which can lead to the formation of new species. This is usually a result of movement of the same species to di erent and isolated environments which blocks the gene ow among the distinct populations, allowing adaptation of characteristics through genetic drift and natural selection?

Divergent evolution

The loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.

Founder e ect

Careful measurements have shown that duck eggs of average size are more likely than smaller or larger eggs to produce viable ducklings. This is an example of?

Stabilizing selection

The evolution of the Galapagos nches from a common ancestral form is thought to have occurred by the mechanism of?

Adaptive radiation

The process through which new species evolve from a single ancestral species while inhabiting the same geographic region.

Sympatric speciation

The evolution of distinct species, despite the populations being geographically adjacent.

Parapatric speciation

Speciation that occurs when biological populations of the same species become isolated due to geographical changes such as mountain building or social changes such as emigration.

Allopatric speciation